Bent Intake Air Passage in Hand Dryers for Noise Leakage Reduction
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Solution Overview
Problem
Existing hand dryers face increased manufacturing costs and reliability issues due to the use of sound-absorbing materials, which can be sucked into the device and cause failures when peeled off, leading to noise leakage.
Innovation Solution
A hand dryer design featuring a high-pressure air-stream generating device, an inner housing, and an outer housing with a projection on the opposing surface that forms a bent intake air passage, guiding air efficiently and reducing noise leakage by minimizing resonance and air stream disturbance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If sound absorbing material is attached to the air passage, then noise leakage is reduced, but manufacturing cost increases and reliability deteriorates due to material peeling and suction risks
Solution Approach 1:
The invention removes the sound absorbing material from the air passage, replacing it with a geometric structure (bent portion) that achieves noise reduction without the reliability issues of attached materials
Solution Approach 2:
The air passage is designed with a bent portion (curved geometry) that reduces noise leakage through its shape, eliminating the need for sound absorbing materials and their associated reliability problems
2Object-generated harmful factors
If sound absorbing material is attached to the air passage, then noise leakage is reduced, but manufacturing cost increases
Solution Approach 1:
The invention extracts the sound absorbing material from the design, replacing it with a geometric feature (bent air passage) that reduces noise without additional material costs
Solution Approach 2:
The bent portion of the air passage uses curved geometry to reduce noise leakage, achieving acoustic performance through shape rather than expensive sound absorbing materials
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively reduces noise while maintaining low manufacturing costs and enhancing product reliability by minimizing noise leakage and resonance, as demonstrated by FFT waveform comparisons.
Implementation Method 1
a high-pressure air-stream generating device (2) for generating a high-pressure air stream
Implementation Method 2
blowing out air from a nozzle to blow water drops off
Implementation Method 3
minimizing resonance and air stream disturbance
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A hand dryer (1) includes an air-stream generating device (2) including a device air inlet (13), an inner housing (3) that accommodates therein the air-stream generating device (2) and has an inner air inlet (7) formed in an intake surface (3a) thereof, and an outer housing (4) that accommodates therein the inner housing (3) and the air-stream generating device (2) and has an outer air inlet (5) formed therein. An intake air passage (11) that connects the outer air inlet (5) and the device air inlet (13) to each other is formed inside the outer housing (4) to include the intake surface (3a) and an opposing surface (4a) as a portion of a wall surface thereof, and a projection (12) is provided on the opposing surface (4a) to project from a region that is opposed to the inner air inlet (7) towards the intake surface (3a). The projection (12) has a first surface (12a) facing an upstream side in the intake air passage (11).